Don't speed to that excess ever, just not worth your life or the life of someone you could potentially hit or injure in an accident, to save a few seconds. Dual carriageway or not, there is no excuse for going over double the speed limit.

Learn from this mistake.

Some info for you from .Gov website:

The minimum penalty for speeding is a £100 fine and 3 penalty points added to your licence.

You could be disqualified from driving if you build up 12 or more penalty points within a period of 3 years.

By law, the vehicle’s registered keeper must be sent a notice of intended prosecution within 14 days of the alleged speeding offence. (this hasn't happened but I'd still expect something).

More importantly:

New drivers

If you’re still within 2 years of passing your driving test, your driving licence will be revoked (withdrawn) if you build up 6 or more penalty points.

You could argue that, but it might still stand. Not 100% sure. Didn't mean to come across preachy, just I've seen too many parents, brothers, sisters etc, grieving, as a result of a family members death as a result of speeding.

You should get a notice of intended prosecution within 14 days of the offence but that is usually for a fixed penalty notice.
As you were 100% over the posted limit and within 2 years of gaining your licence I would be very surprised if a ban was not imposed.
Rule of thumb is that if you are caught going over a third above a posted limit a ban would be considered.
As you were pinged at 66mph I would say with certainty that your speedo was showing over 70mph (allowing for 10% over read).
I strongly suspect that a court letter is looming.
If you are incredibly lucky you may get away with 6 points but taking the short time you have held a licence into consideration, anything less than a ban will be a miracle.
66 in a 30 zone is irresponsible and damned dangerous.
Sorry for being blunt but I have attended far too many fatal RTC where speed and inexperience are a major contributing factor to be subtle in situations like this.

14 days is the point you can argue, you could claim you dont recall who was driving, but as the officer in court would testify it was you who he spoke with, you would have no grounds to stand that argument on. Unfortunately even if it hasnt arrived yet, you should allow up to 6 weeks before thinking that you may be clear, but you may find that if your address is incorrect with the DVLA, worst case scenario a marker is put on your car and a summons issued for your attendance to court.

If you havent heard anything, I would contact your local police station after 4 weeks and ask if there was anything further you should be expecting, better that than being pulled and chucked in the wagon like a true baddie.

On a serious note though, if you rely on your car for work, and you have not got any points on your license already, you MAY get 5 points and a damned hefty fine if the judge feels good, if he doesnt, you will be made an example of, and a ban, extended test, fine and court fee's are likely to be the expected outcome.

Police have 6 months from the date of the incident to start the Court process. Some Police forces will serve papers within weeks of the offence, whereas others will not actually get a file to Court until the 6 months is almost up. You do not have to be served with the Court papers within 6 months, the Police merely have to start the process in that time. Consequently, it may be 7-8 months from the offence before you actually attend Court.

might be time to eat that humble pie,so when you do go to court.stand up apologize profusely,and perhaps say you are willing to be banned so that you can learn from this.and say you will never take your licence for granted again.

Just to add to that 14 days topic, that is 14 days to send the letter, postage delays are not a valid reason even if you never receive the letter at all, as long it was posted within 14 days it's valid the police takes no responsibility for postage issues, Furthermore the 14 days is really for speed camera related issues rather than actual police officers

Correct me if i'm wrong but if the officer did not confirm any fines or points on the spot does that not mean he did not issue any and has left it to the courts?

Therefore is it also not possible to ask about going on a speed awareness course since it's his first offence? (assuming you don't already have a nasty criminal record)

That request would probably be rejected because the speed is more than double anyways...

This happened to my old apprentice, within two years of passing his test, was his dads car so the police turned out to the house as it was mobile camera, after his dad asked what would happen and the answer being fixed penalty, he told the officer his son was driving, few weeks later a summons came through the post and he attended court. he got 6 points and a fine and nothing was mentioned about a ban, his speed was very similar to yours. three days after the court date, he received a letter from DVLA saying as he had got 6 points for speeding within his first two years his licence was now revoked from the following day, he also needed car for work as he had a 10 mile commute at times that was impossible to get to work by public transport, he had to rely on friends, me and family and went straight back in for theory then his test, from revoke to re-passing his test was 6 weeks. he learned the lesson the hard way and yes you would have to resit theory, only plus from this is if you dont learn your lesson, you can only get done for the 6 points in first two years of driving once, but your insurance would soon make you pay.

If you were stopped by the police who spoke to you and cautioned you for speeding a Notice of Intended Prosecution is not necessary as far as I am aware. This means that a summons can be issued against you without further notice.